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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.xml.transform.sax;

import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

/**
 * <p>Acts as an holder for SAX-style Source.</p>
 *
 * <p>Note that XSLT requires namespace support. Attempting to transform an
 * input source that is not
 * generated with a namespace-aware parser may result in errors.
 * Parsers can be made namespace aware by calling the
 * {@link javax.xml.parsers.SAXParserFactory#setNamespaceAware(boolean awareness)} method.</p>
 *
 * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 */
public class SAXSource implements Source {

  /**
   * If {@link javax.xml.transform.TransformerFactory#getFeature}
   * returns true when passed this value as an argument,
   * the Transformer supports Source input of this type.
   */
  public static final String FEATURE =
      "http://javax.xml.transform.sax.SAXSource/feature";

  /**
   * <p>Zero-argument default constructor.  If this constructor is used, and
   * no SAX source is set using
   * {@link #setInputSource(InputSource inputSource)} , then the
   * <code>Transformer</code> will
   * create an empty source {@link org.xml.sax.InputSource} using
   * {@link org.xml.sax.InputSource#InputSource() new InputSource()}.</p>
   *
   * @see javax.xml.transform.Transformer#transform(Source xmlSource, Result outputTarget)
   */
  public SAXSource() {
  }

  /**
   * Create a <code>SAXSource</code>, using an {@link org.xml.sax.XMLReader}
   * and a SAX InputSource. The {@link javax.xml.transform.Transformer}
   * or {@link javax.xml.transform.sax.SAXTransformerFactory} will set itself
   * to be the reader's {@link org.xml.sax.ContentHandler}, and then will call
   * reader.parse(inputSource).
   *
   * @param reader An XMLReader to be used for the parse.
   * @param inputSource A SAX input source reference that must be non-null and that will be passed
   * to the reader parse method.
   */
  public SAXSource(XMLReader reader, InputSource inputSource) {
    this.reader = reader;
    this.inputSource = inputSource;
  }

  /**
   * Create a <code>SAXSource</code>, using a SAX <code>InputSource</code>.
   * The {@link javax.xml.transform.Transformer} or
   * {@link javax.xml.transform.sax.SAXTransformerFactory} creates a
   * reader via {@link org.xml.sax.helpers.XMLReaderFactory}
   * (if setXMLReader is not used), sets itself as
   * the reader's {@link org.xml.sax.ContentHandler}, and calls
   * reader.parse(inputSource).
   *
   * @param inputSource An input source reference that must be non-null and that will be passed to
   * the parse method of the reader.
   */
  public SAXSource(InputSource inputSource) {
    this.inputSource = inputSource;
  }

  /**
   * Set the XMLReader to be used for the Source.
   *
   * @param reader A valid XMLReader or XMLFilter reference.
   */
  public void setXMLReader(XMLReader reader) {
    this.reader = reader;
  }

  /**
   * Get the XMLReader to be used for the Source.
   *
   * @return A valid XMLReader or XMLFilter reference, or null.
   */
  public XMLReader getXMLReader() {
    return reader;
  }

  /**
   * Set the SAX InputSource to be used for the Source.
   *
   * @param inputSource A valid InputSource reference.
   */
  public void setInputSource(InputSource inputSource) {
    this.inputSource = inputSource;
  }

  /**
   * Get the SAX InputSource to be used for the Source.
   *
   * @return A valid InputSource reference, or null.
   */
  public InputSource getInputSource() {
    return inputSource;
  }

  /**
   * Set the system identifier for this Source.  If an input source
   * has already been set, it will set the system ID or that
   * input source, otherwise it will create a new input source.
   *
   * <p>The system identifier is optional if there is a byte stream
   * or a character stream, but it is still useful to provide one,
   * since the application can use it to resolve relative URIs
   * and can include it in error messages and warnings (the parser
   * will attempt to open a connection to the URI only if
   * no byte stream or character stream is specified).</p>
   *
   * @param systemId The system identifier as a URI string.
   */
  public void setSystemId(String systemId) {

    if (null == inputSource) {
      inputSource = new InputSource(systemId);
    } else {
      inputSource.setSystemId(systemId);
    }
  }

  /**
   * <p>Get the base ID (URI or system ID) from where URIs
   * will be resolved.</p>
   *
   * @return Base URL for the <code>Source</code>, or <code>null</code>.
   */
  public String getSystemId() {

    if (inputSource == null) {
      return null;
    } else {
      return inputSource.getSystemId();
    }
  }

  /**
   * The XMLReader to be used for the source tree input. May be null.
   */
  private XMLReader reader;

  /**
   * <p>The SAX InputSource to be used for the source tree input.
   * Should not be <code>null</code>.</p>
   */
  private InputSource inputSource;

  /**
   * Attempt to obtain a SAX InputSource object from a Source
   * object.
   *
   * @param source Must be a non-null Source reference.
   * @return An InputSource, or null if Source can not be converted.
   */
  public static InputSource sourceToInputSource(Source source) {

    if (source instanceof SAXSource) {
      return ((SAXSource) source).getInputSource();
    } else if (source instanceof StreamSource) {
      StreamSource ss = (StreamSource) source;
      InputSource isource = new InputSource(ss.getSystemId());

      isource.setByteStream(ss.getInputStream());
      isource.setCharacterStream(ss.getReader());
      isource.setPublicId(ss.getPublicId());

      return isource;
    } else {
      return null;
    }
  }
}
